Delayed recovery of CDR3 complexity of the T-cell receptor-beta chain in recipients of allogeneic bone marrow transplants who had virus-associated interstitial pneumonia: monitor of T-cell function by CDR3 spectratyping.

Abstract

In the T-cell receptor (TCR)-beta chain, complementary-determining region 3 (CDR3) contains specific peptide sequences essential for recognition. Diversity of this region is considered to contribute to immunocompetence in humans. The purpose of this study was to define the process of reconstitution of CDR3 complexity of the TCR-beta chain after allogeneic bone marrow transplantation and to investigate the association between host immunocompetence and CDR3 complexity. Diversity of the CDR3 region of the TCR-beta chain was examined by CDR3 size distribution analysis with the use of an automated DNA sequencer. Reconstitution of the alphabeta T-cell repertoire and CDR3 diversity was incomplete for at least 2 months after bone marrow transplantation. Delayed reconstitution of T-cell diversity was more marked in immunocompromised hosts. Unlike the situation in patients who received allogeneic bone marrow grafts, the recovery of CDR3 complexity was almost perfect by 2 months after transplantation in patients who received allogeneic blood stem cells. Clonal expansion of alphabeta T cells after allogeneic bone marrow transplantation was readily detected by CDR3 size spectratyping analysis. PCR-based CDR3 size spectratyping may be a useful tool for clinically monitoring immune reconstitution after allogeneic bone marrow transplantation.